- Globally, monitored populations of migratory freshwater fish have declined by an average of 76% between 1970 and 2016. Average declines have been more pronounced in Europe (-93%) and Latin America & Caribbean (-84%).
- Lower declines in North America (-28%) suggest that management of fisheries could result in a lower average decline in abundance.
- The biggest drivers of population decline are habitat degradation, alteration and loss, and over-exploitation. All of these are inextricably linked to human use and impact.
July 28, 2020 – With hydropower, overfishing, climate change and pollution on the rise, monitored populations of migratory freshwater fish species have plummeted by 76% on average since 1970, according to the first comprehensive global report on the status of freshwater migratory fish, issued today by the World Fish Migration Foundation and ZSL (Zoological Society of London). Migratory fish, such as salmon, trout and Amazonian catfish, are vital to meet the food security needs, as well as support the livelihoods of millions of people around the world. In the Danube-Carpathian Region, the Green Heart of Europe, the critically endangered sturgeon once played a major role in local economies, but their stocks have collapsed due to massive overfishing and dams preventing migration. The recovery will take decades but with strong and concerted efforts of all range countries in the Danube, sturgeons could bounce back and again form the basis of sustainable local economies along the Danube and Black Sea. Migratory fish also play a critical role in keeping our rivers, lakes and wetlands healthy by supporting a complex food web. Now, their populations are under immense threat from human-made impacts’ and require urgent action to halt and then reverse the alarming decline.
The report reveals a 76% average decline in populations* for the period of 1970 to 2016 including a staggering average decline of 93% in Europe. This is higher than the rate observed in terrestrial and marine species but in line with the overall decline observed for freshwater vertebrate populations as a whole (83%).1
Monitored sturgeon populations have dramatically declined by 91% on average between 1970 and 2016, with the most commonly recorded threat being exploitation (55%), followed by habitat degradation and change (31%). Mega-fish such as Beluga sturgeon (Huso huso), that used to reach record lengths of 7m are particularly vulnerable. Of the 6 sturgeon species previously present in the Danube Basin, 2 are already considered extinct.
Arjan Berkhuysen, Managing Director of the World Fish Migration Foundation says, “Catastrophic losses in migratory fish populations show we cannot continue destroying our rivers. This will have immense consequences for people and nature across the globe. We can and need to act now before these keystone species are lost for good.”
Habitat degradation, alteration, and loss account for approximately half of the threats to migratory fish. Wetlands are essential habitats for migratory fish species, but, globally, wetlands are disappearing three times faster than forests, while dams and other river barriers block fish from reaching their mating or feeding grounds and disrupt their life cycles.2 Eighty percent of the Danube's floodplains and the floodplains of its main tributaries have been lost.
With 1000 hydropower plants, 400 more are planned or under construction, Bulgaria, Hungary, Slovakia, Romania and Ukraine are already saturated. The Danube catchment is becoming one of the most affected large river catchments not only in Europe but also worldwide. The Danube’s flow is being impeded by the Iron Gates Dams, hindering highly threatened migratory sturgeons and other fish from entering important spawning and feeding sites in the Middle Danube. Alarmingly, the Romanian Government recently modified legislation to open up dam construction in all protected areas across the country.
Over-exploitation, such as unsustainable fishing and accidental by-catch account for around one-third of the threats to migratory fish populations. Despite protection in the Danube sturgeon continue to be threatened by illegal catches. Furthermore, fish populations are threatened by the impacts of the climate crisis as changes in temperature can trigger migration and reproduction, causing these events to happen at the wrong time and misalign reproduction and the period of greater food availability in a specific habitat.
“Migratory fish provide food and livelihoods for millions of people but this is seldom factored into development decisions. Instead, their importance to economies and ecosystems continues to be overlooked and undervalued – and their populations continue to collapse,” said Stuart Orr, WWF Global Freshwater Lead. “The world needs to implement an Emergency Recovery Plan that will reverse the loss of migratory fish and all freshwater biodiversity – for the benefit of people and nature.”
Migratory fish are invaluable to human health and the global economy. Fish and fish by-products represent one of the world’s most traded products within the food sector. The recreational fishing industry alone is worth billions of dollars and tens of thousands of jobs. Overall, the figures represent the need for more protective measures for migratory and freshwater fish worldwide.
WWF-CEE is addressing threats to rivers and wetlands, including dangers posed by inappropriate dams and other infrastructure; promoting guidelines and best practices for the development of hydropower to provide security of planning for investors; and ensuring that clean and renewable energy from water does not come at too great a price in terms of other ecosystem goods and services. Our Slovak colleagues stopped construction of 5 small hydropower projects as well as inappropriate flood protection measures that would have led to the destruction of riparian habitats on the Domizianka River. A court case initiated by WWF-Slovakia regarding the environmental impact assessment (EIA) for a small hydropower station on the Hron River has set a precedent for including cumulative effects in impact assessments for such structures. Advocacy by WWF-Romania and its partners prevented EU funds from financing harmful flood infrastructure projects at Colibita and Gurasada. In a case initiated by WWF, Romania’s highest court ordered a stop to construction of a dam on the Jiu River. In Ukraine, construction of a planned cascade of six hydro plants on the Dniester River has been frozen. The Drava River Campaign with WWF-Adria placed 2 hydropower plants along the Drava on indefinite hold.
A crowdfunding campaign with the support of WWF-Netherlands has enabled WWF-Ukraine to finance the removal of dams in Ukraine that are blocking the migration of Danube salmon (Huchen huchen). Work will begin in the autumn of 2020. WWF-Slovakia will soon follow suit with its own international crowdfunding campaign to remove 2 dams. Another recent crowdfunding campaign enabled WWF-Bulgaria to release 7000 baby Beluga sturgeon into the Danube in June.
“Rivers and migrations are the connective tissue of our planet – and migratory fish are bellwethers for not just rivers, but for the countless other systems they connect, from the deep sea to coastal forests. Losing these fish means losing so much more,” said Jeffrey Parrish, Global Managing Director for Protect Oceans, Land and Water at The Nature Conservancy. “By factoring in these species and systems into sustainable energy and food production, and by investing in their protection and restoration, we can bring them back.”
There is still an opportunity to turn the tide through more research to understand the fate of freshwater migratory fish and by developing practical solutions that restore and protect these animals. Hundreds of hydropower, and dozens of navigation and flood protection infrastructure plans under preparation in Central and Eastern Europe would require proper biodiversity safeguards or be dropped altogether under the EU Water Framework Directive (WFD) in order to ensure that no harm will be done to migratory fish and their habitats.
Furthermore, WWF-CEE is engaged in an on-going seven-year Living Danube Partnership with The Coca-Cola Foundation and the International Commission for the Protection of the Danube River (ICPDR). The Coca-Cola System’s commitment to replacing or replenishing the water that it uses in its products has mobilised financial support for wetland restoration at ten sites across our region. The Partnership most recently completed wetland restoration efforts in Persina and Kalimok along the Bulgarian Danube, improving the circumstances for fish migration and fish breeding.
The authors and organisations associated with this report all call upon the global community to protect free-flowing rivers and guide basin-wide planning by addressing existing threats, adhering to ongoing conservation initiatives and water protection laws, investing in sustainable renewable alternatives to the thousands of new hydropower dams that are planned across the world and fostering public and political will.
Herman Wanningen, Founder of the World Fish Migration Foundation: “The statistics are shocking but we know migratory fish populations can bounce back. We need to act now before populations get to the point where they are too low to recover. Now is the time to value migratory fish and the rivers that sustain them.”
Roxanne Diaz, Communications Manager,
World Fish Migration Foundation
+31 (0) 6 1891 8786
 WWF (2018) Living Planet Report - 2018: Aiming Higher. Grooten, M. and Almond, R.E.A.(Eds). WWF, Gland, Switzerland.
 Gardner, R., Finlayson, C. (2018) Global Wetland Outlook: State of the World’s Wetlands and their Services to People. The Ramsar Convention Secretariat: Gland, Switzerland.
*The average figure was found using abundance information for 1,406 populations of 247 fish species listed on the Global Register of Migratory Species as using freshwater for some of their migration.
More information about the Living Planet Index: The report findings were calculated using the Living Planet Database (LPD, LPI 2020). The authors extracted abundance information for 1,406 populations of 247 fish species listed on the Global Register of Migratory Species (GROMS; Riede 2001).
ZSL (Zoological Society of London) is an international conservation charity working to create a world where wildlife thrives. From investigating the health threats facing animals to helping people and wildlife live alongside each other, ZSL is committed to bringing wildlife back from the brink of extinction.
The World Fish Migration Foundation (WFMF) is an international organisation with a mission to save migratory fish in rivers. The Foundation harnesses global attention for the challenges migratory fish face through a multitude of international, collaborative projects aimed at advocating for obsolete dam removals, and supporting initiatives that open up important swimways.